中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 23 No. 2 February 2013 |
（1. Department of Metallurgy, Beijing General Research Institute of Mining and Metallurgy, Beijing 100070, China;
2. Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 10）
Abstract:Kinetics of Co(II) extraction from sulfate aqueous solution by the sodium salt of di-decylphosphinic acid (Na-DDPA) was studied using a modified Lewis cell to disclose the mechanism of extraction. Parameters affecting the extraction rate, such as stirring speed, temperature, interfacial area, Na-DDPA concentration and Co(II) concentration, were investigated, respectively. The effect of diffusion resistance on extraction rate was negligible when the stirring operation was conducted in a plateau region of 95-110 r/min. Extraction rate increased with the increase in the temperature or specific interfacial area. The activation energy E was calculated to be 32.75 kJ/mol. These suggested that rate controlling mechanism of Co(II) extraction by Na-DDPA was chemical reaction regime and the rate-determining step of Co(II) extraction was chemical reaction at the interface. The initial extraction rate also increased with the increase in the concentrations of Na-DDPA and Co(II). The extraction rate equation and mechanism of Co(II) extraction by Na-DDPA were proposed.
Key words: di-decylphosphinic acid; cobalt; extraction kinetics; extraction
